"Scavenging" on a diesel engine means （）.

A . fuel injectors B . exhaust valves C . intake valves D . all of the above

A . burned exhaust valves B . excessive spring compression C . spring surge D . worn valve seat

A . improve fuel flow volume B . cool the exhaust valves C . reduce the intake air charge density D . increase the temperature of exhaust gase

A . camshaft B . crankshaft C . governor D . flywheel

A . during the valve overlap period B . with only the exhaust valve open C . at a pressure below atmospheric D . without cooling the cylinders or pisto

A . during the valve overlap period B . with only the exhaust valve open C . at a pressure below atmospheric D . without cooling the cylinders or pisto

A . (1) only is correct B . (2) only is correct C . both (1) and (2) are correct D . Neither (1) or (2) are correct

A . the engine to run after the fuel has been secured B . the engine to over-speed C . a fire D . all of the above

A . provide a reservoir for cylinder lubrication B . pump oil into the combustion space for cylinder cooling C . prevent excessive lubricating oil consumption D . allow hydraulic oil film formation on the cylinder

A . a cooling system B . a lubrication oil system C . an electric system D . an injection system

A . it gets dark in color B . a sample rubbed between fingers feels thin C . it has been in use for a specified interval D . it no longer supports combustio

A . (1) only B . (2) only C . both (1) and (2) D . neither (1) nor (2)

A . blows out the exhaust gases B . supplies oxygen for combustion C . cools the valves and cylinder walls D . all of the above

A . diametrical tension B . gap clearance C . radial thickness D . face thickne

A . delivering more air into the cylinder than it would normally receive during an ordinary charging process B . forcing the products of combustion out of the cylinder with the fresh air charge C . collecting the air charge at the cleaner D . combustion and expansion of hot ga

A . over-speeding of the engine B . failure of the engine to shut down C . no effect of engine mounting bolts D . high exhaust temperature

A . combustion gas blow-by B . excessive lubrication C . properly functioning rings D . insufficient cylinder cooling

A . jam in the most worn part of the cylinder when the rings expand B . break in the most worn part of the cylinder when the rings expand C . wear eccentrically on the side opposite the end gap D . overheat and jam at the top center on the combustion stroke

A . a reduction B . an increase C . an outing D . a downward

A . a combination of constant volume and constant pressure B . a combination of constant temperature and constant pressure C . entirely constant pressure D . entirely constant volume

A . piston rod guides B . engine thrust bearing C . crosshead bearing D . main shaft flexible coupling

A . Increases efficiency B . Increases engine horsepower C . Increases engine life D . Reduces engine horsepower

A . Overspeed trip B . Air inlet shut-off valve C . Water injector D . Fuel cutoff valve

A.principle B.principal C.cause D.case